As a social engineer, you spend all of your time manipulating people’s brains. Yet most of the social engineers I meet don’t know the difference between the amygdala and the cerebral cortex.

And you need to.

So this article is going to give you a quick trip through the human brain.

The brain isn’t just a single organism – it’s truly a three-part entity known as the triune brain. The idea of the triune brain was first proposed by Paul MacLean. He proposed that the brain that you and your caveman ancestors shared is not a single brain but actually a three part structure. MacLean viewed our brains as similar to "three interconnected biological computers, [each] with its own special intelligence, its own subjectivity, its own sense of time and space and its own memory.” That is, while each of the three brains interacts, each one functions as a separate and somewhat independent unit.

To get a great idea of the full structure of the brain, check out Dr. Dan Siegel’s video of the “Hand Model of the Brain” on YouTube. This video is an excerpt from his talk at the launch of his latest book, "Mindsight" on January 13, 2010 in Santa Monica.

The Reptilian Brain

The Reptilian is the first brain to evolve (that is, it is the oldest) and is composed of the brain stem and the cerebellum. The Reptilian Brain’s function revolves mainly around ensuring survival and keeping the body well maintained.

Because of the simplicity of this part of the brain, most behavior here is done instinctively, in a procedural manner and impervious to change. This part of the brain is the part active when you reflexively pull your hand away from a hot stove – you don’t consciously think or even emote about the move, your body simply jerks your hand away.

Because of this reflexive behavior, the reptilian brain is involved in the implementation of the fight or flight response: the reptilian brain activates the adrenal glands and gets the heart pumping as you prepare to run, leap and fight from the predator in your midst.

The Limbic Brain

The second oldest brain, as far as evolution is concerned, is the Mammalian or Limbic Brain. This part of our brain is responsible for memory, emotion and judgment. While we think that it is our rational neocortex that helps us make decisions and that spurs us to action, it is truly the structures in the Limbic system that actually drive us to act. In fact, studies have shown that those with damage to the limbic parts of the brain are actually incapable of making decisions.

The limbic system establishes a linkage between emotion and behavior which can affect behavioral impulses generated from the reptilian brains rituals and habits. Certain primal acts also fall under the sphere of the limbic system. The limbic system is the seat of the “fight or flight” response. So, if the reptilian brain implements “fight or flight,” then it is the mammalian brain that determines when it happens. Think about when you get all emotional about a perceived slight – it’s your reptilian brain that actually makes it possible to happen but your emotions drive the actual response.

The limbic system is also where we find maternal/paternal instinct and the hunger and sexual drives. It is noteworthy that since these activities are strongly connected to emotional expression and negotiation, they become rather complicated once the limbic system connects with the neocortex resulting in situations like a state of mixed emotions.

This complication creates an opportunity for the social engineer. Joe Navarro, the renowned influence expert says it this way: “the limbic system was designed not to reason, but to react.” And its role in producing quick reaction leaves it vulnerable to the social engineer. The limbic system’s role in creating emotions and reactions quickly means that it will create honest responses before the neocortex has time to think about its response.

The term “limbic” was coined by Pierre Paul Broca in 1878. It refers to the structures surrounding the brainstem including the amygdala, hypothalamus, and hippocampus:

• The Amygdala: An almond-shaped region of the brain responsible for associating emotions and events. The primary function of the amygdala is the processing of emotions, especially negative emotions such as fear, anger, etc. as well as memory formation.
• The Hippocampus: Responsible mainly for the creation and recall of things that we experience. Damage to the hippocampus is one of the primary causes of amnesia.
• The Hypothalamus: The hypothalamus is primarily concerned with what is known as the “Four F’s”:
o Feeding
o Fighting
o Fleeing
o Fu… uhh… Reproduction

The final part of the brain is the neocortex (also known as the “cerebral cortex”). While it is the most recent development, the neocortex actually constitutes about five-sixths of the mass of the human brain. The highly developed neocortex is the brain structure that differentiates humans from the majority of mammals. While most mammals have some amount of neocortex, it is generally smaller and its absence causes little change to the animal. For instance, a mouse without a neocortex can still move about, still acting like a mouse. However, “a human without a cortex is a vegetable.”

Much of what we consider uniquely human intelligence can be found in the neocortex. This would include abstract intelligence as well as our thought and logic processes. It also includes our speaking and writing abilities. Additionally, the neocortex allows for complex thought – it allows us to picture and foresee consequences of our actions in the future as well as plan to avoid those consequences.

That’s enough information for you to start setting the educational foundation on the brain. And trust me when I say that it will pay dividends when applied not only to your pen testing but also in your understanding of all human interactions. Stay tuned to this very column as we help you apply scientific fact to the art of social engineering.